This dedication you have is inspiring but I think you're finding yourself in a "mini marriage" where you feel obligated to stick it out with him through thick and thin and that's great but it's something that he should EARN. Cheating isn't earning.

That dedication to your partner will be GREAT in the right relationship but right now it's going to hurt you.

He hurt you. It's not your job to sit there next to him and assist him with figuring out why he hurt you.